Way of the walk: What is 'loss of contact'?

In the first of our Way of the walk series ahead of the IAAF World Race Walking Team Championships Taicang 2018 which takes place in the Chinese city on 5-6 May, we chat with 1996 Olympic 20km champion Jefferson Perez of Ecuador and Australia's 2004 Olympic 20km bronze medallist Jane Saville to find out more about the discipline's loss of contact rule.